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compiler-constructionflex-lexerlexical-analysis

How to match with smaller than operator in flex?

I am trying to match the strings in a file with the regular expressions in flex. For example, to match with assignment operator, I write:

= printf("tASSIGN token");

But when I want to match with the operator <, it doesn't accept the following line:

< printf("tLT token");

What can I do?

Solution

  • The < character is special to lex -- it is used to mark a pattern as only applying in certain states. To get a literal < you need to escape or quote it:

    "<"    printf("tLT token");